Safety brake-operating mechanism



Sept. 22, 1925. 1,554,752

E. osEs SAFETY'BRAKE OPERATING MECHANISM Filed April 20. 1921 2Sheets-Sheet 1 r HI Q A TTORNEYS Sept. 22, mars 1,554,752

E. Q. MOSES SAFETY BRAKE OPERATING MECQANISM Filed April 20. 1921 2Sh'eets-5heet 2 WTORNEV) Bil latented Sept. 22, l925- UNITED STATESPATENT OFFICE.

EDMUND oUINoY MOSES,'OF NEW YORK, N. Y.

SAFETY BRAKE-OPERATIN G MECHANISM.

Application filed April 20, 1921.

ei chanisiu, ot which the following is a iecitication.

This invention relates to operating mechanism tor brakes, and especiallyfor vehicle brakes. lt is well known that practically all motor vehiclesand some other vehicles are provided with, what are commonly terined,emergency brakes, and one of the important functions t these brakes isfor locking the car s ationary when not-in use, particularly when a caris standing on a grade. For locking the bralres in applied position,mechanism is provided, usually some term of pawl and ratchetuechanisn'i, associatedwith the brake applying lever.

ll hen the vehicle is standing on grade, it necessary to pull the leverwith sutlicieut force to apply the brake so tightly that accidentalnioveinent the vehicle is iinpossible, the pawl and ratchet mechanismbeing intended to hold the lever in this position. Many accidents,howtweu have oecurred by reason oi the failure of the brake to beapplied with sutlicieut force to positively prevent movement oitthevehicle.

in such (arses owing to vibration, oran accidental push given to thevehicle or from other causes the vehicle may start to roll down thegrade, sometimes with disastrous results, he failure of the brakes tohold usually occurs "from carelessness on part of the operator whenapplying the brake, insntlicient force being utilized to apply the braketightly. The danger ot the brake slipping after it has seentiingly beenapplied in such a way as to hold the car, may also be due to the coolingnit of the brake band and drum, previously heated by friction, in

such a way as to decrease the holding power of the brake, therebypern'iitting the vehicle to start.

The primary object of the present invention is to insure that the brakeshall be initially applied with a force adequate to insure themaintenance of the braking etlect, so as to positively lock the vehicleagainst accidental inovenzent illustrated this is accomplished bvutiliz- In the constructions braKe drum 2 fixed thereto.

Serial No. 463,067.

ing mechanisms of such character, that the brake cannot be held inapplied position unless suflicient force has beenutilized to up ply itproperly.

Another object of the invention is to pro vide a construction which willininintiizc the danger of dragging brakes.v Thisis accomplished by thepresent invention bccausethe hralie locking mechanism in preferred formwill not operate to hold the brake partly applied but is so arrangedthat when the brake is once released it will be cou'ipletely releasedand not held in an intermediate position; in other words, the brake willbe either locked in fully applied position in which the car cannot bedriven or the brake will be completely released, so that there will beno dragging. The danger of the brake jun'iping into partly appliedposition, owing to the vehicle striking an obstruction in the road asoccurs in some vehicles, is also eliminated.

In the accon'ipanying drawings, in which I have shown some preferredembodiments of my invention,

Figure 1 is a side elevation showing a brake applying lever andmounting, illustrating one mode of application of the in vention.

Figure 2 is a similar view showinga modified brake lever construction.

Figure 3 is a view showing the construction oi Figure 2,atter theapplication oil? the brake applying force.

Figure 4 is a section on line lVlV of Figure 2. a

Figure 5 is a view'similar to Figures 1 and 2, illustrating anotherembodiment oi. the invent-ion.

Figure 6 is a section on line VI VI of Figure 5. I 5

Figure 7 is a view of another modified construction.

F igure'S is a section on line VIIIVIII of Figure 7.

Figure 9 is a view illustrating another niiodified construction.

Figure 10 is a diagrammatic view of an automobile chassis showing theapplication of the invention thereto.

Referring to the drawings in detail, and

especially to Figure 10, 1 designates the rear wheel of an automobile,having the usual 3 is the brake band, which is adapted to be drawntightly about the drum 2, by a toggle mechanism 4, which may be of anyusual construction. Power is applied to the toggle mechanism by means ofsuitable linkage, including a pull rod 5, which is arranged to beoperated by the emergency brake level-'6. The latter is pivoted upon apivot 7, carriedby a suitable fulcrum support 8, which in many motorvehicles of present-day construction, forms a part of or is mounted uponthe transmission gear casing of the vehicle. Obviously, the brakeapplying lever may be mounted in any. suitable location or manner.

In the construction illustrated, the support 8 also carries a curvedrack or segment 9, having ratchet teeth 10, formed thereon. Referringnow more particularly to the'specilic construction illustrated in Figure1, it will be seen that the pull rod 5 is not directly connected to thelever 6, as is the usual construction in ordinary brake mechanism. 011the contrary, the pull rod 5 is pivoted to one arm 12 01 a bell cranklever, which is pivoted at 13 to the lower end oi the lever 6v The otherarm 14 of the bell crank lever is used to actuate the pawl mechanism,the latter to operate with the teeth on the segment 9 when sutlicientforce is applied to the brake lever.

in the construction illustrated, this pawl mechanism is constructed asfollows: A rod 15': is mounted parallel with the lever G and is arrangedto slide in guides 16, 17 and 15;, carried by the lever G. This rod 15has fixed to its lower end a block 19, to which is pivoted a pawl 20.The pawl 20 is provided with a shoulder 21, adapted to engage the blockand limit the swinging movement of the pawl with respect to the block inone direction. A small spring 22 tends to hold this shoulder inengagement with this block but will yield to permit a limited pivotalmovement of the pawl in one direction. The rod 15 has a collar 23 fixedthereto and a spring 24 interposed between this collar and upper end ofthe'guide 18 tends to lift the rod 15 and the pawl 20, so as to normallyhold the pawl 20 out of engagement with the teeth on the segment 9. Acoil spring 25 somewhat stiffer than the spring 24 is interposed betweenthe arm 14 of the bell crank and the block 19. Normally this spring isnot under sufiicient tension, however, to overcome the spring 24, sothat until force is applied to the brake lever, the pawl 20 remains outof engagement with the teeth onthe segment. Connected to the upper endof the rod 15 is a hand grip lever 26 of suitable construction adaptedwhen moved toward the handle 6 in the usual manner to pull up on the rod15 for the purpose of releasing the brake, as will be hereinafterexplained hen the brake is to be applied, the hancated at to receive thepins 31.

dle of the lever 6 is grasped and drawn toward the left. This will exerta pull upon the rod 5 and will draw up on the brake band and apply thebrake. At first, however, the force of the spring 24 will be sufficientto hold the rod 15 and pawl 20 in raised position, so that the pawl willnot catch on the segment and the brake cannot be locked in an appliedposition but the lever 6 will simply return to its initial position, ifthe pressure of the hand thereon is released.

If, however, considerable force is applied to.

the lever (3, the pull of the pull rod acting upon the arm 12 of thebell crank lever will cause the arm 14 to push down on the stiff spring25 with such force as to overcome the spring 24:, and thereby force downthe rod 15, block 19 and pawl 20, until the pawl 20 engages the teeth10.

It the pressure of the hand on the brake lever be now released, theengagement ot the pawl 20 with the teeth will hold the brake in firmlyapplied position. By properly proportioning the length of the bell cranklever arms and the strength of the spring 24:, the pawl 20 may be madeto engage the teeth 10 only after the application of sufiicient force tothe brake lever to apply the brake band so tightly that danger ofaccidental movement of the vehicle is entirely eliminated. Until thissafe and sutlicient pressure has been applied,- the brake cannot belocked at all but will inunediately be released upon the release oi thepressure upon the brake lever. This entirely eliminates the danger of heapplication of insufficient braking force. The pivoted construction ofthe pawl described permits the pawl to ride freely over the teeth 10after it has been brought down into contact therewith, it turtherapplication of the brake is desired. The pawl, however, will immediatelytake hold oi any tooth as soon as the motion of the brake lever ceases.When it is desired to release the brake, the hand grip lever 26 ispressed towards the brake lever handle. thereby pulling up on the rod 5,block 19 and pawlv 20, the spring 25 yielding so as to permit this to bedone. 7

In Figures 2, 3 and t, I have illustrated a modified construction forcarrying out the invention, in which the lower end 01" the rod 15, whichis slidingly mounted upon the lever G, is "formed to provide the pawl 20for engagement with the teeth 10 on the segment 9. Fixed to the rod 15is a block or enlargement 30 having pins 31 projecting from it, to whichare attached a pair of strong coil springs 32. The other ends oi": thesprings 32 are attached to a cross pin 33, carried by a projection onthe lever 6. Also pivoted to the lever 6 are a pair of links 34, slottednear their free ends as indi- The springs 82 and links 34; are soproportioned and arranged that when the rod 15 is in its upper position,as shown in Figure 2,

the line connecting pins 31 and 33, which represents the line of tensionof the springs 34, passes above the point of pivotal sup port 36 of thelinks 34;. The springs 3% thus tend to hold the rod 15 raised andthe'pawl out of engagement with the teeth on the segment. It the rod 15,however, he forced downwardly, the pins 31 will move downwardly untilthe line of the springs passes below the pivot point 36, when thetension ot the springs S lwill serve to hold the rod 15 and pawldepressed, so that the pawl will engage the segment teeth 10. The brakepull rod 5 is connected to one arm 37 of a bell crank lever, the otherarm 38 of which is forked and engages the block on the rod 15. Normallythe rod will occupy its raised position as shown in Figure 2.

When sirflicient pressure is applied to'the brake lever 6, the pull onthe bell cranklever will force the rod 15 downwardly, as shown in Figure3. As soon as sutlicient force has been applied to stretch the springs34 to such an extent that the line of tensionot' the springs passes thedead center, as repre sented by the pivotal point 36, then the pawl 20will snap quickly down into engagement with the segment teeth and thesprings 34: will act to hold the pawl 20 firmly in engagement with thesegment teeth, while at the same time permitting the pawl. to snap overthe teeth in the direction or": further application of the brake. hen itis desired to release the brake, manipulation of the hand grip lever 26will lift the pawl out oi engagement with the segn'ient teeth. and uponrelieving the pressure upon the brake lever, will restore the parts'tothe positions shown in Figure 2. r

In Figures 5 and 6, I have shown another modification oi the invention,in which the brake lever 6 has pivoted to its lower end, a lever 40having an arm 41 to which the brake pull rod is attached. The lever 40also has a hook-shaped pawl portion 42, adapted to engagethe teeth onthe segment 9. The lever 40 normally held in such position that the pawl42 is out of engagement with the teeth on the segment, the means forholding it in this position comprising a spring pressed, wedgeshapedplunger 41-3, mounted on the stem 44, slidable in guides on the lever 6.A spring 45 acts to urge the plunger 43 downwardly. The wedge-shapedplunger engages in a similarly shaped'notch 46in the curved up persurface of the lever 40.. The engagementor the plunger with'this'notchprevents the movement. of the lever 4-0, so as to bring the pawl l2 inengagement with the seg ment until sutlicient force has been applied tothe pull rod 5 to force the plunger out of the notch. The desired forcemay be determined by giving a proper inclination to the engagingsurfaces of the plunger and notch, and by using a spring of requisitestrength. When the plunger has once been forced out ot'the notch, itwill ride on the curved surface of the lever. A spring a? is preferablyprovided for holding the pawl 42 yieldingly in engagement with the teethon the segment, although this is not essential as the pull of the brakeupon the pull rod 5 also tends to keep the pawlin engagement with thesegment teeth. For releasing the brake, a hand grip lever 26 is,provided, which is arrangedto pull upwardly a rod 15, which operates ahell crank lever 48, the depending arm of which engages a pin 49,projecting from the lever 40. By operating tne bell crank lever 48, thelever 40 may be restored to the position shown in Figure 5, when theplunger 43 will snap back into the notch 46.

IirFigures 7 and 8, another form of the invention is shown, in which thebrake lever 6 has pivoted to its lower end, a lever member 50, to whichis attached the brake pull rod'5 and which has a pawl portion 51,adapted'to engage the teeth on the segment 9. A strong coil spring 52 isattached at its lower end to a pin 53, projecting from the lever 50, andat its upper end to a pin 54 projecting from the brake lever 6. N01mally the axis of the spring passes to the lett'of the pivotal supportof the lever 50, so that the spring tends to hold the lever50 in theposition shown in Figure 7, with the pawl 51 out of engagement with thesegment teeth. When sufficient pressure is applied to the braking lever,however, the force of the spring 52 will be overcome and the lever '50will be swung about its pivot until the axis of the spring 52 passes thecenter of pivotal support 55 ot the lever 50. The pawl 51 will then bebrought into engagement with the segment and will be maintained inactive position by the combined pull of the brake'rod' and of the spring52. To release the brake and restore the lever member 50 to normalposition, a hand grip lever 26 and rod 15 are employed.

In Figure 9, 'I have shown another modi- 'lication' of the invention, inwhich a lever member is pivoted at 61 to the brake lever 6. Alsopivotedto the member 60 are the brake pull rod 5-and the hand grip rod 15.Themember 60 is provided with a. pawl portion 62 adapted to engage theteeth upon the segment 9 when sufficient force is applied to the brake.A jack knife spring 63 is attached to the lever 6 and normallyengagestheflat surfacetl l on the lever member 60, 1 thereby holding the samein normal position with the pawl portion 62 out of engagement with thesegment 9 until sutficient force has been applied to cause the spring 63to yield. lVhen the point 65 of the member 60 passes the dead centerposition, then the spring 63 will tend to hold the pawl portion 62 in emgagement with the teeth on the segment.

It will be seen that the constructions above described provide means forlocking the brake in applied position only after a predetermined forcehas been employed, so that the brake can only be locked on when it hasbeen drawn suiliciently tight to positively prevent movement of thevehicle.

It will also be noted that most of the mechanisms described are of suchcharacter that when once the locking pawl has been broughtintoengagement with the segment, it will be caused to firmly engagetherewith and that there is no danger of the pawl be coming accidentallydisplaced, so as to re lease the brake. For instance, with theconstruction shown in Figures 2, 8 and 4, the

pawl is only applied after suiiicient force has been utilized to swingthe toggle mechanism, con'iprising the links 34: and springs 32, pastthe dead center. As soon as this has been done, however, springs 32 thentend to maintain the pawl in engagementwith the segment, so thataccidental displacement of the pawl is impossible and the brake is firm-1y locked on until the hand grip lever is actuated.

Another valuable feature of the construction shown is that in the caseof weakening or breakage of the spring means utilized, the brake willnot fail to work nor will the pawl mechanism be rendered inoperative insuch a way as to prevent locking on of the brake. For instance, in theconstruction shown in Figures 2, 3 and 4, if the springs 32 shouldbreak, the brake could still be applied by manipulating the brake leverin the usual manner and the pawl would still engage the rack teeth andbe held in engagement therewith by a pull. of the rod 5. The onlydifference would be that the brake could be locked on at any pointinstead of only after the application of the predetermined pressure. Thebrake in fact would function exactly as brakesin use at present nowfunction.

lVhile I have shown and described in detail, certain preferredembodiments of my invention, I realize that the same may be embodied inother constructions, and I do not wish to limit myself tothe particularmeans set forth. On the contrary, I intend to cover my invention broadlyin whatever form its principle may be embodied.

Having thus-describedmy invention, I claim:

a 1. The combination with a vehicle brake, of means for locking thebrake in applied position and means sensitive to the amount of brakeapplying force for controlling the action of the said locking means.

2. The combination with a vehicle brake, of means for applying the same,and means for locking the same applied after the application of apredetermined applying force, said locking means being incapable oflocking the brake in applied posit-ion until the application of saidforce.

3. The combination with a vehicle brake, of means for applying the same,and means for preventing the locking of the brake in applied positionwhen applied with insutficient force to prevent accidental movement ofthe vehicle.

4. The combination with a vehicle brake, of a lever for applying thesame, pawl and ratchet mechanism for locking said lever in brakeapplying position, and means for preventing the operation of said pawland ratchet mechanism until predetermined force has been applied to thebrake.

5. The combination with a vehicle brake, of a lever for applying thesame, a pawl and ratchet mechanism for locking the brake lever in brakeapplying position, and yielding means depending upon the force appliedto the brake for governing the operation of the pawl and ratchetmechanism.

6. The combination of a brake, means for applying the same, a yieldingconnection between said brake and said applying means adapted to yieldupon the application of a brake applying force, and means normally heldout of action by said yielding connection for locking the brake inapplied position, said locking means coming into action only upon theyielding of said yielding connection.

7. The combination of a brake rod, a brake lever brake locking meansassociated with said brake lever, a movable member connecting said brakerod and lever and operatively associated with the brake locking meansand a spring arranged to oppose the movement of said movable memberduring application of said brake.

8. The combination of a brake rod, a brake lever, and brake lockingmeans, said brake locking means including a movable member constitutinga connection between the brake rod and the brake lever and yieldingmeans arranged to resist the movement of said movable member during theinitial part of the movement of the brake applying lever.

In testimony whereof I have afiixed my signature to this specification.

' EDMUND QUINCY MOSES.

